high 8.7

CVE-2026-55995 json

Double-free in the iSNS attribute decoder in open-iscsi

published 2026-07-29 3 mo ago modified 2026-07-30 3 mo ago also EUVD-2026-50330

cvss: 8.7; version 4.0, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.3%; EPSS 0.3% chance of exploitation in 30 days, percentile 16%
public exploits: 0; none known

A Double Free vulnerability in open-iscsi allows an unauthenticated MITM attacker to cause DoS.

This issue affects open-iscsi: from ? through 56718d4e9d1a4f51c30697b5c0534144bb41c9bb.

Patch / fix

distros 7 links 1

debian ubuntu red hat opensuse almalinux rocky linux azure linux

open-isns Debian 14 0.103-2

debian advisories DEBIAN-CVE-2026-55995

open-isns Ubuntu 22.04 LTS 0.101-0ubuntu2.1
open-isns Ubuntu 24.04 LTS 0.101-0.3ubuntu0.1
open-isns Ubuntu 26.04 LTS 0.101-2.1ubuntu0.1
open-isns Ubuntu Pro 18.04 LTS 0.97-2ubuntu0.1~esm1
open-isns Ubuntu Pro 20.04 LTS 0.97-3ubuntu0.1~esm1

ubuntu advisories UBUNTU-CVE-2026-55995

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

isns-utils RHEL 8 0.99-1.el8_10.1
isns-utils-libs RHEL 8 0.99-1.el8_10.1
isns-utils RHEL 9 0.101-4.el9_8.1
isns-utils-libs RHEL 9 0.101-4.el9_8.1
isns-utils RHEL 10.2 0.103-1.el10_2.1
isns-utils-libs RHEL 10.2 0.103-1.el10_2.1
isns-utils RHEL 8.4 EUS_LONG_LIFE, RHEL 8.4 AUS 0.99-1.el8_4.1
isns-utils-libs RHEL 8.4 EUS_LONG_LIFE, RHEL 8.4 AUS 0.99-1.el8_4.1

red hat advisories RHSA-2026:61249 RHSA-2026:60385 RHSA-2026:60333 RHSA-2026:59999 RHSA-2026:59996 RHSA-2026:60005

open-isns openSUSE Tumbleweed 0.103+4.60de8b5-1.1

opensuse advisories openSUSE-SU-2026:11456-1

isns-utils AlmaLinux 10 0.103-1.el10_2.1
isns-utils-libs AlmaLinux 10 0.103-1.el10_2.1
isns-utils AlmaLinux 9 0.101-4.el9_8.1
isns-utils-libs AlmaLinux 9 0.101-4.el9_8.1
isns-utils AlmaLinux 8 0.99-1.el8_10.1
isns-utils-libs AlmaLinux 8 0.99-1.el8_10.1

almalinux advisories ALSA-2026:53846 ALSA-2026:53847 ALSA-2026:53848

isns-utils Rocky Linux 10 0.103-1.el10_2.1
isns-utils Rocky Linux 9 0.101-4.el9_8.1
isns-utils Rocky Linux 8 0.99-1.el8_10.1

rocky linux advisories RLSA-2026:53846 RLSA-2026:53847 RLSA-2026:53848

isns-utils Azure Linux 3.0 0.102-2

azure linux advisories AZL-94434

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

github.com/open-iscsi/open-isns@56718d4 commit

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-55995 updated 2026-08-31 cvss 7.5

open-isns: open-iscsi: Denial of Service via double-free in iSNS attribute decoder

Red Hat Enterprise Linux BaseOS (v. 8) isns-utils 0.99-1.el8_10.1, isns-utils-libs 0.99-1.el8_10.1
fixed: vendor fix RHSA-2026:53848
Red Hat Enterprise Linux BaseOS (v. 9) isns-utils 0.101-4.el9_8.1, isns-utils-libs 0.101-4.el9_8.1
fixed: vendor fix RHSA-2026:53847
Red Hat Enterprise Linux BaseOS (v. 10) isns-utils 0.103-1.el10_2.1, isns-utils-libs 0.103-1.el10_2.1
fixed: vendor fix RHSA-2026:53846
Red Hat Enterprise Linux BaseOS AUS (v.8.4) isns-utils 0.99-1.el8_4.1, isns-utils-libs 0.99-1.el8_4.1
fixed: vendor fix RHSA-2026:61249
Red Hat Enterprise Linux BaseOS AUS (v.8.6) isns-utils 0.99-1.el8_6.1, isns-utils-libs 0.99-1.el8_6.1
fixed: vendor fix RHSA-2026:60385
Red Hat Enterprise Linux BaseOS E4S (v.8.8) isns-utils 0.99-1.el8_8.1, isns-utils-libs 0.99-1.el8_8.1
fixed: vendor fix RHSA-2026:60333
Red Hat Enterprise Linux BaseOS E4S (v.9.2) isns-utils 0.101-4.el9_2.1, isns-utils-libs 0.101-4.el9_2.1
fixed: vendor fix RHSA-2026:59999
Red Hat Enterprise Linux BaseOS E4S (v.9.4) isns-utils 0.101-4.el9_4.1, isns-utils-libs 0.101-4.el9_4.1
fixed: vendor fix RHSA-2026:59996

show 5 more

Red Hat Enterprise Linux BaseOS EUS (v. 10.0) isns-utils 0.103-1.el10_0.1, isns-utils-libs 0.103-1.el10_0.1
fixed: vendor fix RHSA-2026:60005
Red Hat Enterprise Linux BaseOS EUS (v.9.6) isns-utils 0.101-4.el9_6.1, isns-utils-libs 0.101-4.el9_6.1
fixed: vendor fix RHSA-2026:60006
Red Hat Enterprise Linux BaseOS EUS EXTENSION (v.8.4) isns-utils 0.99-1.el8_4.1, isns-utils-libs 0.99-1.el8_4.1
fixed: vendor fix RHSA-2026:61249
Red Hat Enterprise Linux BaseOS EUS EXTENSION (v.8.6) isns-utils 0.99-1.el8_6.1, isns-utils-libs 0.99-1.el8_6.1
fixed: vendor fix RHSA-2026:60385
Red Hat Enterprise Linux BaseOS TUS (v.8.8) isns-utils 0.99-1.el8_8.1, isns-utils-libs 0.99-1.el8_8.1
fixed: vendor fix RHSA-2026:60333

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation: none
Automatable: yes
Technical impact: partial
Assessed: 3 mo ago (2026-07-29)

Exploit prediction

0.25% chance of exploitation in the next 30 days, higher than 16% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	4.0	8.7	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
CNA	4.0	8.7	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Affected products

open-iscsi open-iscsi

Classification

Weakness

CWE-415 Double Free

References

Sources

CVE List CVE-2026-55995
NVD CVE-2026-55995

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary